Removal of nitric oxide from flue gas using water-soluble iron(II) dithiocarbamates

The reactions of glycine and iminodiacetic acid with carbon disulfide in strongly alkaline solution yield N-(carboxymethyl) dithiocarbamate (1) and N,N-bis(carboxymethyl)dithiocarbamate (2), respectively. These dithiocarbamates have been characterized by UV-visible and laser Raman spectroscopies and have been isolated as S-benzylthiuronate derivatives. Aqueous solutions containing iron(II) chelates of 1 and 2 have been shown to be effective in removing NO from a simulated flue gas mixture over the pH range of 3-10. Most of the absorbed NO was reduced to N sub(2), and oxidative coupling of the dithiocarbamates occurred to form the corresponding dithiuram disulfides. Evidence is also presented for the absorption of NO by iron(II) chelates of dithiocarbamates derived from diethanolamine and urea.